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8
result(s) for
"Demirezer, L Ömür"
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Chemical Composition, Antioxidant and Anticholinesterase Activities of the Essential oil of Origanum rotundifolium Boiss. from Turkey
by
Özek, Temel
,
Demirezer, L. Ömür
,
Özbek, Hilal
in
Alzheimer's disease
,
Antioxidants
,
Chromatography
2017
The essential oil was obtained by hydrodistillation from the aerial parts of Origanum rotundifolium Boiss. Its chemical content and composition were analyzed by using a gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Total phenolic content of the essential oil was determined as 132.39 µg gallic acid equivalent by Folin–Ciocalteu’s method and the major component was identified as carvacrol (56.8 %) along with p-cymene (13.1 %), (Z)- b -ocimene (5.4 %), b -caryophyllene (3.9 %), borneol (3.4 %) and thymol (3.2 %). After chemical characterization, the essential oil was evaluated for its antioxidant activity by DPPH free radical, superoxide anion radical and hydrogen peroxide scavenging activities as well as ferrous ion-chelating power test, ABTS radical cation decolorization assay and ferric thiocyanate methods. Besides antioxidant activity, acetylcholinesterase and butyrylcholinesterase inhibitory activities of the essential oil were also evaluated by Ellman’s method. It demonstrated inhibitory activities on AChE and BuChE, key enzymes in the pathogenesis of Alzheimer’s disease (AD), in addition to significant antioxidant activity.
Journal Article
Chemical Composition, Antioxidant Capacity, Acetyl- and Butyrylcholinesterase Inhibitory Activities of the Essential Oil of Thymus haussknechtii Velen
2016
The chemical composition of the essential oil from the aerial parts of Thymus haussknechtii Velen. was analyzed by using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The major component of the essential oil was thymol (52.2%). Total phenolic content of the essential oil was determined as 132.9 µg gallic acid equivalent. The antioxidant capacity was evaluated by DPPH free radical, superoxide anion radical and hydrogen peroxide scavenging activities along with ferrous ion-chelating power test, ABTS radical cation decolorization assay and ferric thiocyanate methods. In addition to antioxidant activity, anticholinesterase activity of the essential oil was also evaluated. It exhibited inhibitory activities on AChE and BuChE which play an important role in Alzheimer's disease, along with significant antioxidant activity.
Journal Article
Adulteration Determining of Pharmaceutical Forms of Ginkgo biloba Extracts from Different International Manufacturers
2014
In this study, Ginkgo biloba products used for the same purpose, but licensed to varying authorities were analyzed in point of similarity to each other. A group of these products were licensed from health authorities as herbal medicinal product (HMP), while the other groups of products were licensed as the food supplement (FS). The evaluation of their phytoequivalence was carried out comparing the chromatographic fingerprint profiles. Furthermore, ginkgolides (ginkgolides GA, GB, GC, and GJ) and flavonoid aglycones (quercetin, kaempferol, and isorhamnetin) were quantitatively analyzed by using liquid chromatography-mass spectrometry (LC-MS) and HPLC-diode Array detector (HPLC-DAD) assays. All six herbal medicinal products and two food supplements were found to be phytoequivalent to each other, but five of the seven food supplements did not possess similar content as herbal medicinal products, and the quantity of ginkgolides and flavonoid aglycones per tablet/capsule was found to be lower than declared on the labels. In addition, food supplements were found to be adultered with rutin to reach expected total flavonoid glycosides amount.
Journal Article
HPLC Fingerprinting of Sennosides in Laxative Drugs with Isolation of Standard Substances from Some Senna Leaves
2011
Senna leaves are one of the oldest medicinal herbs and they are used as laxative. Herbal teas which contain senna leaves are most commonly used to promote weight loss. The quality control of slimming teas which contain Senna leaves and also pharmaceutical preparations including Senna extract enriched by sennoside B was achieved by HPLC fingerprinting method. While the presence of sennoside A and B in laxative drugs was proved, it was seen to be devoid of sennosides in slimming teas. Kaempferol 3-O-β-D-gentiobioside (1), aloe-emodine 8-O-β-D-glucopyranoside (2), rhein 8-O-β-D-glucopyranoside (3), torachrysone 8-O-β-D-glucopyranoside (4), isorhamnetine 3-O-β-D-gentiobioside (5) were also isolated from Senna leaves.
Journal Article
Phenylpropanoids, Sesquiterpenoids and Flavonoids from Pimpinella tragium Vill . subsp. lithophila (Schischkin) Tutin
2016
A new sesquiterpenoid named germacradiene-6 -O-(6'-O-acetyl)-β-D-glucoside (1) and a new flavonol glycoside named rhamnetin-3-O-(2''-O- β-D-glucopyranosyl)- β-D-galactopyranoside (2), along with three known sesquiterpenoids dictamnol (3), radicol (4), germacradiene glucoside (5); three phenylpropanoids 4-methoxy-2-(3-methyloxiranyl)-phenyl 2-methylbutanoate (6), 4-methoxy-2-(3-methyloxiranyl)-phenyl angelate (7), thellungianin E (8); and a flavonol glycoside platanoside (9) were isolated from the aerial parts of Pimpinella tragium Vill . subsp. lithophila (Schischkin) Tutin. Their structures were elucidated by detailed analyses of 1D and 2D NMR, UV, IR and HR-ESI-MS data.
Journal Article
Phenolic Compounds from Cotinus Coggygria Scop. with Alpha Glucosidase Inhibition
2019
(Anacardiaceae) is used in Turkish folk medicine to treat DM. [...]the bioguided fractionation and isolation studies were carried on C. coggygria. The inhibition of the key enzymes in digestion of dietary starch such as a-amylase and a-glucosidase provides to control blood glucose level (Hamid et al., 2015). [...]of this study five phenolic compounds were isolated as well as the assessment of their a-glucosidase and a-amylase inhibition effects. The glucose core with one or more galloyl groups is necessary to interact with and stimulate the receptor target (Ren et al., 2006). [...]it should be stated that compound 2 was inactive against a-glucosidase because of lack of a sugar moiety.
Journal Article
Isolation of a flavonoid, apigenin 7-O-glucoside, from Mentha longifolia (L.) Hudson subspecies longifolia and its genotoxic potency
by
Orhan, Furkan
,
Gulluce, Medine
,
Demirezer, Lutfiye Omur
in
Acridines - toxicity
,
Ames test
,
Antimutagenic Agents - isolation & purification
2015
Mentha is a medicinal and aromatic plant belonging to the Lamiaceae family, which is widely used in food, flavor, cosmetic and pharmaceutical industries. Recently, it has been found that the use of Mentha as a pharmaceutical source is based on its phytochemical constituents that have far been identified as tannins, saponins, phenolic acids and flavonoids. This study was designed to evaluate the mutagenic and antimutagenic activities of apigenin 7-O-glucoside (A7G), a flavonoid isolated from Mentha longifolia (L.) Hudson subspecies longifolia (ML). The possible antimutagenic potential of A7G was examined against mutagens ethyl methanesulfonate and acridine in an eukaryotic cell system Saccharomyces cerevisiae and sodium azide in Salmonella typhimurium TA1535 and 9-aminoacridine in S. typhimurium TA1537. According to our findings, any concentrations of the A7G used did not show mutagenic activity but exerted strong antimutagenic activities at tested concentrations. The inhibition rates for the Ames test ranged from 27.2% (S. typhimurium TA1535: 0.4 μM/plate) to 91.1% (S. typhimurium TA1537: 0.2 μM/plate) and for the yeast deletion assay from 4% to 57.7%. This genotoxicological study suggests that a flavonoid from ML owing to antimutagenic properties is of great pharmacological importance and might be beneficial to industries producing food additives, cosmetics and pharmaceuticals products.
Journal Article